JP2020164667A - Agricultural film and agricultural/horticultural facility - Google Patents

Abstract

To provide a film that has a large change in light scattering in the range of about 0°C to 40°C.SOLUTION: The agricultural film has at least one layer composed of a continuous phase and a dispersion phase, in which (A) the ratio of the cross-section area of the dispersion phase having a circle equivalent diameter of 1 μm or more and 10 μm or less among the dispersion phases to the cross-section area of the layer is 1% or more and 30% or less, and (B) the coefficient of linear expansion satisfies 1.5×10-4K-1 or more and 2.8×10-4K-1 or less.SELECTED DRAWING: None

Description

The present invention relates to agricultural films and agricultural and horticultural facilities.

Patent Document 1 describes a composition composed of a plurality of resins having different temperature dependences of refractive index from each other, and the difference in refractive index between the resins is 2 × ^10-2 or less at at least one temperature within the operating temperature range. A transparent resin molded body formed from the resin composition to be used is described.

Japanese Unexamined Patent Publication No. 2001-12307

Agricultural films have high light scattering properties in the summer when the sunlight is strong, which not only prevents damage such as leaf burning of crops caused by excessive direct light, but also prevents the decrease in the amount of solar radiation throughout the year. Is required to do. Therefore, there is a demand for an agricultural film that exhibits low light scattering property at low temperature in winter, high light scattering property at high temperature in summer, and has a large change depending on the temperature of the light scattering property.

The inventor of the present invention has a large change in light scattering property in the film because the linear expansion coefficient in the direction perpendicular to the film surface having at least one layer consisting of a continuous phase and a dispersed phase is within a predetermined range. Moreover, they have found that the rigidity is high, and have completed the present invention.

On the other hand, Cited Document 1 does not describe the relationship between the coefficient of linear expansion of the entire film and the change in light scattering property of the film. Further, in the transparent resin molded product of the example described in Cited Document 1, since the amount of polyethylene added is as small as 5 wt%, the coefficient of linear expansion of the entire film is considered to be small.

One aspect of the present invention is to provide a film having a large change in light scattering property in the range of about 0 ° C. to 40 ° C. and excellent rigidity.

In order to solve the above problems, the agricultural film according to one aspect of the present invention has at least one layer composed of a continuous phase and a dispersed phase, and satisfies the following (A) and (B);
(A) A cross section of the dispersed phase having a circular equivalent diameter of 1 μm or more and 10 μm or less in the cross section cut in the direction perpendicular to the film surface and in the direction parallel to the slow phase axis in the film surface. The ratio of the area is 1% or more and 30% or less with respect to the cross-sectional area of the layer.
(B) The coefficient of linear expansion calculated by the following formula (1) is 1.5 × 10 ^-4 K ^-1 or more and 2.8 × 10 ^-4 K ^-1 or less.
Coefficient of linear expansion = (L _{25 ° C-} L _{0 ° C} ) / (25 ° C-0 ° C) (1)
Here, L _{25 ° C.} represents the length of the film in the direction perpendicular to the film surface at 25 ° C., and L _{0 ° C.} represents the length of the film in the direction perpendicular to the film surface at 0 ° C. ..

In addition, another preferred embodiment of the present invention is an agricultural and horticultural facility in which the above-mentioned agricultural film is spread on an agricultural and horticultural facility frame.

According to one aspect of the present invention, it is possible to provide a film having a large change in light scattering property in the range of about 0 ° C. to 40 ° C. and high rigidity.

Hereinafter, one embodiment of the present invention will be described in detail.

<Agricultural film>
The agricultural film according to one embodiment of the present invention is a film having at least one layer composed of a continuous phase and a dispersed phase, and has a coefficient of linear expansion in a direction perpendicular to the film surface (also referred to as a thickness direction). Is 1.5 × 10 ^-4 K ^-1 or more and 2.8 × 10 ^-4 K ^-1 or less. The agricultural film according to one embodiment of the present invention can be suitably used as an outer or lining film for a greenhouse for plant cultivation, a covering material for a tunnel, and the like.

(Coefficient of linear expansion)
In the present specification, the coefficient of linear expansion is the ratio of the amount of change in length ΔL to the amount of change in temperature ΔT, and is represented by ΔL / ΔT. In the present specification, the coefficient of linear expansion in the direction perpendicular to the surface of the agricultural film according to one aspect of the present invention is calculated by the following formula (1).

Coefficient of linear expansion = (L _{25 ° C-} L _{0 ° C} ) / (25 ° C-0 ° C) (1)
Here, L _{25 ° C.} is the length of the film perpendicular to the film surface at 25 ° C., and L _{0 ° C.} is the length of the film perpendicular to the film surface at 0 ° C. That is, the agricultural film according to one aspect of the present invention adopts the film thickness as a reference for the length for obtaining the coefficient of linear expansion.

According to the inventor of the present invention, (i) when the film is a single layer, the coefficient of linear expansion in the thickness direction of the layer composed of the continuous phase and the dispersed phase, which will be described later, and (ii) the film is composed of the continuous phase and the dispersed phase. When the film has a layer and other layers, it has been found that the coefficient of linear expansion in the thickness direction of the film as a whole has a great influence on the change in the light scattering property of the film, and the present invention has been completed. There is.

The agricultural film according to one embodiment of the present invention has a linear expansion coefficient of 1.5 × 10 ^-4 K ^-1 or more and 2.8 × 10 ^-4 K ^-1 or less in the direction perpendicular to the film surface, and 1 It is more preferably .7 × 10 ^-4 K ^-1 or more and 2.6 × 10 ^-4 K ^-1 or less. When the coefficient of linear expansion is 1.5 × 10 ^-4 K ^-1 or more and 2.8 × 10 ^-4 K ^-1 or less, the light scattering property is enhanced in the summer when the temperature reaches around 40 ° C, and the light scattering property is enhanced in the winter when the temperature reaches around 0 ° C. The light scattering property can be lowered. Specifically, the haze value can be increased in the summer when the temperature reaches around 40 ° C., and the haze value can be decreased in the winter when the temperature reaches around 0 ° C. Further, when the coefficient of linear expansion is 2.8 × 10 ^-4 K ^-1 or less, the rigidity of the film can be increased. Specifically, the value of 1% SM, which will be described later, can be increased. When the coefficient of linear expansion of the film is smaller than 1.5 × 10 ^-4 K- ¹ , the change in light scattering property in the temperature range of 0 ° C to 40 ° C becomes small. Specifically, the change in haze value in the temperature range of 0 ° C. to 40 ° C. becomes small. Further, when the coefficient of linear expansion of the film is larger than 2.8 × 10 ^-4 K ^-1 , the rigidity of the film is lowered.

The coefficient of linear expansion is measured using a test piece obtained by cutting a film into a size of 5 mm × 5 mm. The thermomechanical analyzer was set to compression mode, the test piece was cooled to -15 ° C or lower under the condition of a load of 0.05 N, and then the temperature was raised to 60 ° C at a rate of 5 ° C / min to 0 ° C. The length in the direction perpendicular to the surface at 25 ° C., that is, the thickness is measured, and the coefficient of linear expansion is obtained from the above equation (1). The coefficient of linear expansion is measured in a helium atmosphere. The thickness of the film is not specified in the measurement of the coefficient of linear expansion. However, as will be described later, the continuous phase of the film is such that the coefficient of linear expansion of the test piece cut out from the film is 1.5 × 10 ^-4 K ^-1 or more and 2.8 × 10 ^-4 K ^-1 or less. The ratio of the thickness of the layer composed of the dispersed phase and the material constituting the film are determined.

The coefficient of linear expansion of the agricultural film according to one aspect of the present invention may be obtained as the coefficient of linear expansion of only the layer when the agricultural film consists of only a layer consisting of a continuous phase and a dispersed phase, and is continuous. When a layer other than the layer composed of the phase and the dispersed phase (that is, other layers described later) is provided, it is preferable to obtain the coefficient of linear expansion of the agricultural film composed of all of these layers. That is, the agricultural film according to one aspect of the present invention has at least one layer composed of a continuous phase and a dispersed phase, and has a linear expansion coefficient in the direction perpendicular to the film surface including the layer of 1.5 × 10 ^−. By determining the layer composition of the film so that it is ⁴ K ^-1 or more and 2.8 × 10 ^-4 K ^-1 or less, the change in haze value in the temperature range of 0 ° C to 40 ° C is increased. Can be done. The agricultural film according to one aspect of the present invention has [continuous phase] and [dispersion] so that the linear expansion coefficient is 1.5 × 10 ^-4 K ^-1 or more and 2.8 × 10 ^-4 K ^-1 or less. It can be produced by appropriately adjusting the conditions of the raw materials and the production method described later in [Phase] and [Other layers]. When the coefficient of linear expansion is 1.5 × 10 ^-4 K ^-1 or more and 2.8 × 10 ^-4 K ^-1 or less, the light scattering property is enhanced in the summer when the temperature reaches around 40 ° C, and the light scattering property is enhanced in the winter when the temperature reaches around 0 ° C. The light scattering property can be lowered. That is, the change in light scattering property can be increased in the range of about 0 ° C. to 40 ° C.

The coefficient of linear expansion is adjusted to be 1.5 × 10 ^-4 K ^-1 or more and 2.8 × 10 ^-4 K ^-1 or less by adjusting the following (a) and (b) as appropriate. can do.
(A) Types and ratios of components of each phase in the layer consisting of continuous phase and dispersed phase (b) Ratio of layer thickness consisting of continuous phase and dispersed phase in film The above (a), (b) and line The details of the relationship with the expansion coefficient will be described later.

Hereinafter, when the term "linear expansion coefficient" is used in the present specification, the "linear expansion coefficient" is the coefficient of linear expansion in the direction perpendicular to the film surface calculated by the above equation (1) unless otherwise specified. Show that.

The agricultural film having the above-mentioned coefficient of linear expansion can be produced by appropriately adjusting the conditions of the raw material and the production method. As the layer composed of the continuous phase and the dispersed phase (and the layer other than the layer composed of the continuous phase and the dispersed phase) contained in the agricultural film, a resin composition which is a general raw material of the agricultural film can be used. .. As a raw material for a layer composed of a continuous phase and a dispersed phase, a thermoplastic resin that is different from a thermoplastic resin that is a continuous phase, organic particles and inorganic particles that are a dispersed phase, and a thermoplastic resin that is a continuous phase is particularly used. It is advisable to use at least one selected from the above in an appropriate combination. When the dispersed phase is a thermoplastic resin different from the continuous phase thermoplastic resin, the layer composed of the continuous phase and the dispersed phase is a phase in which the continuous phase thermoplastic resin and the dispersed phase thermoplastic resin are in phase. It has a separated sea island structure. The sea portion of the sea-island structure becomes a thermoplastic resin having a continuous phase, and the island portion becomes a thermoplastic resin having a dispersed phase. A more preferable raw material for a layer composed of a continuous phase and a dispersed phase will be described later in [Layer composed of a continuous phase and a dispersed phase]. As the raw material of the layer other than the layer composed of the continuous phase and the dispersed phase, a general thermoplastic resin may be used, and it is preferable to use a polyolefin resin (hereinafter, a layer other than the layer composed of the continuous phase and the dispersed phase). Is also referred to as a polyolefin-based resin layer). The conditions of a more preferable production method will be described later in <Agricultural film production method>.

(Haze value)
In this specification, the haze value is measured by using a temperature control haze meter (THM-150TL) manufactured by Murakami Color Technology Research Institute Co., Ltd. in accordance with JIS K 7136: 2000 for measurement conditions other than temperature. Value. In the present specification, the light scattering property of the film can be evaluated by the haze value.

The agricultural film according to one embodiment of the present invention preferably has a haze value at 40 ° C. of 45% or more, and more preferably 50% or more. When the haze value at 40 ° C. is 45% or more, the light irradiated to the film can be suitably scattered in the summer when the amount of solar radiation is large.

Further, in the agricultural film according to one aspect of the present invention, the difference between the haze value at 0 ° C. and the haze value at 40 ° C. is, for example, 30% or more, more preferably 35% or more, and 40 ° C. The haze value at 0 ° C. is higher than the haze value at 0 ° C. Therefore, it is possible to prevent the light irradiated on the film from being scattered in the winter when the amount of solar radiation is small.

(1% secant elastic modulus)
The 1% secant elastic modulus is measured using a test piece obtained by cutting a film into a width of 20 mm and a length of 125 mm. In the present specification, the 1% secant modulus (1% Secant Modulus, hereinafter abbreviated as 1% SM) is applied to a tensile tester (for example, manufactured by Shimadzu Corporation, AGS-100B) at a distance between chucks of 5 cm. It is a value calculated by the following formula (2) from the load value at the time of mounting, pulling at a speed of 5 mm / min, and measuring 1% extension.
1% SM = F / S / 0.01 (2)
Here, F represents the load when the test piece is extended by 1%, and S represents the initial area of the cross section perpendicular to the tensile direction of the test piece. The initial area is the area before the tensile test is performed.

In the agricultural film according to one aspect of the present invention, 1% SM is preferably larger than 18 MPa, more preferably 20 MPa or more, and even more preferably 22 MPa or more.

From the viewpoint of ensuring light scattering in the summer when the temperature reaches around 40 ° C., the thickness of the film is preferably 1 μm or more, more preferably 30 μm or more. From the viewpoint of lowering the light scattering property and reducing the weight of the film to improve the handleability in winter when the temperature reaches around 0 ° C., it is preferably 500 μm or less, more preferably 300 μm or less. The thickness of the film described in this paragraph is the thickness of the film that can be measured at room temperature (23 ° C.), and L _{25 ° C.} and L _{0 ° C.} in the formula (1) for obtaining the coefficient of linear expansion are not necessarily the same. It does not match.

[Layer consisting of continuous phase and dispersed phase]
The layer composed of the continuous phase and the dispersed phase is the main layer constituting the agricultural film according to one aspect, and is simply described as "layer" in the present specification, and unless otherwise specified, the "layer" is used. "" Indicates a layer composed of a continuous phase and a dispersed phase.

The agricultural film according to one embodiment of the present invention has a circle-equivalent diameter of the dispersed phases in a cross section of the film cut in a direction perpendicular to the film surface and in a direction parallel to the slow axis in the film surface. The ratio of the cross-sectional area of the dispersed phase in which is 1 μm or more and 10 μm or less is preferably 1% or more and 30% or less, and more preferably 2% or more and 25% or less with respect to the cross-sectional area of the layer. .. The slow axis in the film plane can be obtained by using a phase difference measuring device (KOBRA (registered trademark) series manufactured by Oji Measuring Instruments Co., Ltd.) based on the parallel Nicol rotation method. When the ratio of the cross-sectional area of the dispersed phase having a circle equivalent diameter of 1 μm or more and 10 μm or less is within the range of 1% or more and 30% or less, the light scattering property is enhanced in the summer when the temperature reaches around 40 ° C. Light scattering can be reduced in winter when the temperature reaches.

In the present specification, the dispersed phase is a phase composed of at least one selected from organic particles dispersed in a continuous phase, inorganic particles, and a thermoplastic resin different from the thermoplastic resin of the continuous phase. That is, the circle-equivalent diameter of the dispersed phase means the circle-equivalent diameter of the dispersed phase obtained for each observed dispersed phase. The shape of the dispersed phase is not particularly limited. Here, the "circle equivalent diameter" means the diameter of a circle having the same area as the cross-sectional area of one dispersed phase reflected in the cross section of the photographed layer, and is an image from an image obtained by photographing the cross section of the agricultural film. Can be determined by the analysis system.

In the resin composition constituting the layer composed of the continuous phase and the dispersed phase, the mixing ratio of the components constituting the continuous phase and the components constituting the dispersed phase has a linear expansion coefficient of 1.5 × 10 ^-4 K ^-1. Adjust appropriately so that the above is 2.8 × 10 ^-4 K ^-1 or less. For example, the lower the dispersed phase ratio in the layer consisting of the continuous phase and the dispersed phase, the higher the linear expansion coefficient can be adjusted, and the higher the dispersed phase ratio, the lower the linear expansion coefficient. can do.

When the total amount of the components constituting the continuous phase and the components constituting the dispersed phase is 100 parts by mass, the content of the components constituting the continuous phase is preferably 50 parts by mass or more, more preferably 60 parts by mass. It is 50 parts by mass or more, more preferably 65 parts by mass or more, and particularly preferably 70 parts by mass or more. The content of the components constituting the continuous phase is preferably 98 parts by mass or less, more preferably 95 parts by mass or less, further preferably 90 parts by mass or less, and particularly preferably 85 parts by mass or less. is there.

Further, when the total amount of the components constituting the continuous phase and the components constituting the dispersed phase is 100 parts by mass, the content of the components constituting the dispersed phase is preferably 2 parts by mass or more, more preferably. It is 5 parts by mass or more, more preferably 10 parts by mass or more, and particularly preferably 15 parts by mass or more. Further, it is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, further preferably 35 parts by mass or less, and particularly preferably 30 parts by mass or less. When the content of the components constituting the dispersed phase is 50 parts by mass or less, sufficient elongation and breaking strength can be ensured. The coefficient of linear expansion can be adjusted to be higher as the content of the components constituting the dispersed phase is reduced, and the coefficient of linear expansion can be lowered as the content of the components constituting the dispersed phase is increased.

[Continuous phase]
The continuous phase preferably contains a thermoplastic resin. The thermoplastic resin may be a thermoplastic resin capable of forming a portion corresponding to the sea in the sea-island structure, and is not limited, but has a coefficient of linear expansion rather than a component used for forming a dispersed phase. Is preferably large. A polyolefin-based resin is mentioned as a more preferable thermoplastic resin for adjusting the linear expansion coefficient of the layer composed of the continuous phase and the dispersed phase within the above range. Examples of the polyolefin-based resin include ethylene-based copolymers and propylene-based polymers.

(Ethylene copolymer)
Examples of the ethylene-based copolymer include an ethylene-vinyl ester copolymer, a copolymer of ethylene and an unsaturated carboxylic acid and / or a derivative thereof (hereinafter, also referred to as an ethylene-unsaturated carboxylic acid (derivative) copolymer). ), Ethylene-α-olefin copolymer and the like. The ethylene-based copolymer may be used alone, or two or more types of ethylene-based copolymers may be used in combination.

The ethylene-vinyl ester copolymer is an ethylene-vinyl ester copolymer having a monomer unit derived from ethylene and a monomer unit derived from vinyl ester as a main monomer unit. The ethylene-vinyl ester copolymer may be a random copolymer of a monomer derived from ethylene and a monomer derived from vinyl ester, or may be a block copolymer.

Examples of the vinyl ester used as a constituent material of the ethylene-vinyl ester copolymer include vinyl esters of fatty acids, which have 2 to 4 carbon atoms, and more specifically, Examples thereof include vinyl acetate and vinyl propionate. In one aspect of the present invention, the ethylene-vinyl ester copolymer may contain a monomer unit derived from two or more kinds of vinyl esters. Above all, the vinyl ester is preferably vinyl acetate.

Specific examples of the ethylene-vinyl ester copolymer having a monomer unit derived from ethylene and a monomer unit derived from vinyl ester include an ethylene-vinyl acetate copolymer and an ethylene-vinyl acetate. Examples thereof include ethylene-vinyl acetate copolymers (EVA), and ethylene-vinyl acetate copolymers (EVA) are particularly preferably used. Further, the ethylene-vinyl ester copolymer may be used alone, or two or more kinds of ethylene-vinyl ester copolymers may be used in combination.

Further, the ethylene-vinyl ester copolymer may contain a monomer unit derived from a monomer other than ethylene and vinyl ester.

Commercially available products that can be used as ethylene-vinyl ester copolymers include, for example, Evertate (registered trademark) (manufactured by Sumitomo Chemical Co., Ltd.), Sumitate (registered trademark) (manufactured by Sumitomo Chemical Co., Ltd.), Novatec (registered trademark). ) EVA (manufactured by Nippon Polyethylene Co., Ltd.), Ultrasen (registered trademark) (manufactured by Tosoh Co., Ltd.), Suntech (registered trademark) EVA (manufactured by Asahi Kasei Co., Ltd.), Evaflex (registered trademark) Made) and the like.

In the ethylene-vinyl ester copolymer, the content of the monomer unit derived from vinyl ester is preferably 7% by mass or more and 30% by mass or less, and more preferably 10% by mass or more and 28% by mass or less. More preferably, it is 12% by mass or more and 25% by mass or less.

Further, in the ethylene-vinyl ester copolymer, the content of the monomer unit derived from ethylene is preferably 70% by mass or more and 93% by mass or less, and more preferably 72% by mass or more and 90% by mass or less. More preferably, it is 75% by mass or more and 88% by mass or less.

When two or more types of ethylene-vinyl ester copolymers are used in combination as the ethylene-vinyl ester copolymer, the content E of the ethylene-derived monomer unit in the copolymer is calculated by the following formula (3). Ru.
E (mass%) =
(E ₁・ W ₁ + E ₂・ W ₂ +… + _Em・ W _m ) / (W ₁ + W ₂ +… W _m ) (3)
(However, ethylene-vinyl ester copolymer 1, ethylene-vinyl ester copolymer 2, ... Ethylene-vinyl ester copolymer m of m-type ethylene-vinyl ester copolymers are used in combination (m is 3 or more). The content (% by mass) of the ethylene-derived monomer unit in the ethylene-vinyl ester copolymer _k is E _k , and the content of the ethylene-vinyl ester copolymer _{k in} the resin composition is W. and _k (integer k from 1 to m).)
Similarly, when two or more types of ethylene-vinyl ester copolymers are used in combination as the ethylene-vinyl ester copolymer, the content E'of the monomer unit derived from the vinyl ester in the copolymer is expressed by the following formula. Calculated according to (4).
E'(mass%) =
_{(E '1 · W 1 +} E' 2 · W 2 + ... + E 'm · W m) / (W 1 + W 2 + ... W m) (4)
(However, copolymer 1, copolymer 2, ... m type copolymer of copolymer m is used in combination (m is an integer of 3 or more), and a single amount derived from the vinyl ester in the copolymer k. Let E'k be the content (% by mass) of the body unit, and W _{k be} the content of the copolymer _{k in} the resin composition (k is an integer from 1 to m).
The content of ethylene-derived monomeric units and the content of vinyl ester-derived monomeric units in the ethylene-vinyl ester copolymer can be quantified by the saponification method, and is more specific. If the ethylene-based copolymer is an ethylene-vinyl acetate copolymer, it can be quantified according to JIS K 7192: 1999.

The melt flow rate (MFR) of the ethylene-vinyl ester copolymer is preferably 0.05 g / 10 minutes or more and 20 g / 10 minutes or less, and more preferably 0.1 g / 10 minutes or more and 15 g / 10 minutes or less. is there. The MFR is measured by the A method under the conditions of a temperature of 190 ° C. and a load of 21.18 N according to JIS K 7210: 1999.

The ethylene-unsaturated carboxylic acid (derivative) copolymer contains a monomer unit derived from ethylene and a monomer unit derived from an unsaturated carboxylic acid and / or a derivative thereof as a main monomer. An unsaturated carboxylic acid (derivative) copolymer. The ethylene-unsaturated carboxylic acid (derivative) copolymer may be a random copolymer of a monomer derived from ethylene and a monomer derived from unsaturated carboxylic acid and / or a derivative thereof, and may be blocked. It may be a copolymer.

Examples of the unsaturated carboxylic acid used as a constituent material of the ethylene-unsaturated carboxylic acid (derivative) copolymer include unsaturated monocarboxylic acids such as (meth) acrylic acid, crotonic acid, isocrotonic acid, and 3-butenoic acid; maleic acid. , Unsaturated dicarboxylic acids such as fumaric acid, etc., but are not limited thereto. Among them, unsaturated monocarboxylic acid is preferable, and for example, (meth) acrylic acid is preferable. In this specification, acrylic acid and methacrylic acid are collectively referred to as (meth) acrylic acid.

Examples of the unsaturated carboxylic acid derivative used as the constituent material of the ethylene-unsaturated carboxylic acid (derivative) copolymer include the above-mentioned unsaturated carboxylic acid salt, unsaturated carboxylic acid ester, acid anhydride, and unsaturated carboxylic acid amide. Examples thereof include unsaturated carboxylic acid imides, preferably salts of unsaturated carboxylic acids and unsaturated carboxylic acid esters. Examples of the unsaturated carboxylic acid salt include sodium salt, potassium salt, calcium salt, zinc salt and the like of unsaturated carboxylic acid. Examples of the unsaturated carboxylic acid ester include unsaturated carboxylic acid alkyl esters such as unsaturated carboxylic acid methyl ester, unsaturated carboxylic acid ethyl ester, and unsaturated carboxylic acid butyl ester; and unsaturated carboxylic acid aryl such as unsaturated carboxylic acid phenyl ester. Esters; unsaturated carboxylic acid glycidyl esters and the like can be mentioned.

As a specific example of the ethylene-unsaturated carboxylic acid (derivative) copolymer having a monomer unit derived from ethylene and a monomer unit derived from an unsaturated carboxylic acid and / or a derivative thereof in the present invention. , Ethylene-unsaturated carboxylic acid copolymer such as ethylene- (meth) acrylic acid copolymer; part of the carboxyl group of ethylene-unsaturated carboxylic acid copolymer such as ethylene- (meth) acrylic acid copolymer Or an ionomer in which all is neutralized with metal ions such as sodium, potassium, calcium, and zinc; ethylene- (meth) methyl acrylate copolymer, ethylene- (meth) ethyl acrylate copolymer, ethylene- (meth) acrylic. Examples thereof include ethylene-unsaturated carboxylic acid ester copolymers such as butyl acid acid copolymers, and in particular, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) methyl acrylate copolymer, and ethylene-. Ethylene (meth) acrylate copolymer and the like are preferably used. Further, in one aspect of the present invention, the ethylene-unsaturated carboxylic acid (derivative) copolymer contains two or more unsaturated carboxylic acids and / or monomer units derived from the derivatives thereof. You may.

Specific examples of the ethylene-unsaturated carboxylic acid (derivative) copolymer include the following.

(I) Ethylene-unsaturated carboxylic acid copolymer Nuclel (registered trademark) (ethylene-methacrylic acid copolymer, manufactured by Mitsui-Dupont Polychemical Co., Ltd.)
(Ii) Ionomer Hymilan® (registered trademark) in which some or all of the carboxyl groups of the ethylene-unsaturated carboxylic acid copolymer are neutralized with metal ions. Some of the carboxyl groups of the ethylene-methacrylic acid copolymer are zinc ions. Or ionomer neutralized with sodium ions, manufactured by Mitsui-Dupont Polychemical Co., Ltd.) (iii) Ethylene-unsaturated carboxylic acid ester copolymer Acryft (registered trademark) (ethylene-methyl methacrylate copolymer, Sumitomo Chemical Co., Ltd.) , Lexpearl (registered trademark) EMA (ethylene-methyl acrylate copolymer, manufactured by Nippon Polyethylene Co., Ltd.), Lexpar (registered trademark) EEA (ethylene-ethyl acrylate copolymer, manufactured by Nippon Polyethylene Co., Ltd.) , Rotril (registered trademark) (ethylene-methyl acrylate copolymer or ethylene-butyl acrylate copolymer, manufactured by Alchema), Elvalois (registered trademark) AC (ethylene-methyl acrylate copolymer, ethylene-acrylic acid) Either an ethyl copolymer or an ethylene-butyl acrylate copolymer, manufactured by DuPont)
The ethylene-unsaturated carboxylic acid (derivative) copolymer may be used alone, or two or more kinds of ethylene-unsaturated carboxylic acid (derivative) copolymers may be used in combination.

The content of the monomer unit derived from the unsaturated carboxylic acid and / or its derivative in the ethylene-unsaturated carboxylic acid (derivative) copolymer is the light due to the rigidity of the film and the temperature change (0 ° C to 40 ° C). In consideration of the change in scattering property (haze value), it is preferably more than 10% by mass and 40% by mass or less, more preferably 15% by mass or more and 35% by mass or less, and further preferably 20% by mass or more and 30% by mass. The mass is 100% by mass or less (however, the mass of the ethylene-unsaturated carboxylic acid (derivative) copolymer is 100% by mass).

The content of the monomer unit derived from the unsaturated carboxylic acid and / or its derivative in the ethylene-unsaturated carboxylic acid (derivative) copolymer can be measured by infrared absorption spectrum analysis.

The content of the monomer unit derived from ethylene in the ethylene-unsaturated carboxylic acid (derivative) copolymer is the change in the light scattering property (haze value) with the rigidity of the film and the temperature change (0 ° C to 40 ° C). From the viewpoint of the above, it is preferably 60% by mass or more and 90% by mass or less, more preferably 65% by mass or more and 85% by mass or less, and further preferably 70% by mass or more and 80% by mass or less (however, ethylene- The mass of the unsaturated carboxylic acid (derivative) copolymer is 100% by mass).

The content of the monomer unit derived from ethylene in the ethylene-unsaturated carboxylic acid (derivative) copolymer is the monomer unit derived from the unsaturated carboxylic acid and / or its derivative measured by the infrared absorption spectrum analysis method. Can be calculated by subtracting the content of from 100% by mass.

When two or more types of ethylene-unsaturated carboxylic acid (derivative) copolymers are used in combination as the ethylene-unsaturated carboxylic acid (derivative) copolymer, the content of ethylene-derived monomer units in the copolymer E Is calculated by the following formula (5).
E'' (mass%) =
_{(E '' 1 · W '} 1 + E''2 · W' 2 + ··· + E '' m · W 'm) / (W' 1 + W '2 + ··· W' m) (5)
(However, m species of ethylene-unsaturated carboxylic acid (derivative) copolymer 1, ethylene-unsaturated carboxylic acid (derivative) copolymer 2, ... ethylene-unsaturated carboxylic acid (derivative) copolymer m The ethylene-unsaturated carboxylic acid (derivative) copolymer of the above is used in combination (m is an integer of 2 or more), and the ethylene-unsaturated carboxylic acid (derivative) copolymer k contains a monomer unit derived from ethylene. The amount is _E''k , and the content of the copolymer _{k in} the resin composition is _W'k (k is an integer from 1 to m).

The melt flow rate (MFR) of the ethylene-unsaturated carboxylic acid (derivative) copolymer is preferably 0.1 g / 10 minutes or more and 10 g / 10 minutes or less from the viewpoint of processing into a film. The MFR is measured by the A method or the B method under the conditions of a temperature of 190 ° C. and a load of 21.18 N according to JIS K7120: 1999.

The ethylene-α-olefin copolymer is an ethylene-α-olefin copolymer having a monomer unit derived from ethylene and a monomer unit derived from α-olefin as main monomers. .. The ethylene-α-olefin copolymer may be a random copolymer of a monomer derived from ethylene and a monomer derived from α-olefin, or may be a block copolymer.

The content of the ethylene-derived monomer unit in the ethylene-α-olefin copolymer is preferably 50% by mass or more and 90% by mass or less, more preferably 55% by mass or more and 85% by mass or less, and further. It is preferably 60% by mass or more and 80% by mass or less (however, the mass of the ethylene-α-olefin copolymer is 100% by mass).

The monomer derived from the α-olefin preferably has 3 to 20 carbon atoms, and examples of the ethylene-α-olefin copolymer include ethylene-1-butene copolymer and ethylene-1. -Pentene copolymer, ethylene-1-hexene copolymer, ethylene-1-heptene copolymer, ethylene-1-octene copolymer and the like can be mentioned. Of these, ethylene-1-butene copolymers, ethylene-1-hexene copolymers, and ethylene-1-octene copolymers are particularly preferable. Further, an ethylene-propylene copolymer may be used as long as the content of the monomer unit derived from ethylene is 50% by mass or more. As the ethylene-α-olefin copolymer, a copolymer of ethylene and two or more kinds of α-olefins may be used.

The ethylene-α-olefin copolymer contributes to the provision of a film having excellent strength. From the viewpoint of obtaining a high-strength film, the ethylene-α-olefin copolymer is preferably obtained by polymerizing ethylene and α-olefin using a metallocene catalyst.

Examples of commercially available products that can be used as the ethylene-α-olefin copolymer include the following. Excellen (registered trademark) FX (Sumitomo Chemical Co., Ltd.), Toughmer (registered trademark) (Mitsui Chemical Co., Ltd.), ENGAGE (registered trademark) (Dow Chemical), AFFINITY (registered trademark) (Dow Chemical) , EXACT (registered trademark) (manufactured by ExxonMobile), kernel (registered trademark) (manufactured by Japan Polyethylene Corporation).

As the ethylene-α-olefin copolymer, a single ethylene-α-olefin copolymer may be used, or two or more kinds of ethylene-α-olefin copolymers may be used in combination.

(Propylene polymer)
Examples of the propylene-based polymer include a propylene homopolymer, a copolymer of propylene and ethylene and / or an α-olefin having 4 or more carbon atoms, and among them, propylene and ethylene and / or a copolymer having 4 or more carbon atoms. Copolymers with α-olefins are preferred.

The content of the monomer unit derived from propylene in the copolymer of propylene and ethylene and / or α-olefin having 4 or more carbon atoms is preferably 70% by mass or more and 99% by mass or less (however, however). The mass of the copolymer of propylene and ethylene and / or α-olefin having 4 or more carbon atoms is 100% by mass).

When the propylene-based polymer is a copolymer of propylene and ethylene and / or an α-olefin having 4 or more carbon atoms, a monomer unit derived from ethylene and / or an α-olefin having 4 or more carbon atoms. The content is preferably 1% by mass or more and 30% by mass or less (however, the mass of the copolymer of propylene and ethylene and / or α-olefin having 4 or more carbon atoms is 100% by mass).

The melt flow rate (MFR) of the propylene-based polymer is preferably 0.05 g / 10 minutes or more and 20 g / 10 minutes or less, and more preferably 0.1 g / 10 minutes or more and 15 g / 10 minutes or less. The MFR is measured by the A method under the conditions of a temperature of 230 ° C. and a load of 21.18 N according to JIS K 7120: 1999.

In addition to the thermoplastic resin, the continuous phase is selected from at least a light stabilizer, an ultraviolet absorber, an antifogging agent, an antioxidant, an antifog agent, a lubricant, and the like, as long as the effects of the present invention are not impaired. It may contain one additive.

[Dispersed phase]
The dispersed phase preferably contains at least one component selected from a thermoplastic resin different from the organic particles, the inorganic particles and the continuous phase thermoplastic resin. The agricultural film according to one aspect of the present invention can be adjusted so that the coefficient of linear expansion becomes higher as the ratio of the dispersed phase having a circle equivalent diameter of 1 μm or more and 10 μm or less in the layer composed of the continuous phase and the dispersed phase is lowered. The linear expansion coefficient can be adjusted to be lower as the dispersion phase ratio of the equivalent circle diameter of 1 μm or more and 10 μm or less is increased, so that the linear expansion coefficient is 1.5 × 10 ^-4 K ^-1 or more. As already explained, it can be adjusted to 8 × 10 ^-4 K ^-1 or less. The component of the dispersed phase in the layer composed of the continuous phase and the dispersed phase may be any of organic particles, inorganic particles, and a thermoplastic resin different from the thermoplastic resin of the continuous phase. The refractive index of the component contained in the dispersed phase is not particularly limited, but is preferably 1.50 or more and 1.53 or less, more preferably higher than 1.50 and lower than 1.53, and more preferably 1.51. It is more preferably 1.52 or more, and most preferably 1.51 or more and lower than 1.52. When the refractive index of the components contained in the dispersed phase is 1.50 or more and 1.53 or less and the linear expansion coefficient is within the above range, the light scattering property of the film is improved in the summer when the temperature reaches around 40 ° C. It can be increased, the light scattering property can be lowered in winter when the temperature reaches around 0 ° C., and the difference in light scattering property depending on the height difference of the temperature can be increased. The refractive index is a value measured by the particle immersion method at room temperature, and here, the value of the refractive index after the third decimal place is rounded off.

(Organic particles)
Examples of the organic particles include crosslinked acrylic particles. Examples of the crosslinked acrylic particles include crosslinked copolymer particles of (meth) acrylic acid ester and styrene (crosslinked MMA-St copolymer particles). Examples of the (meth) acrylate ester include methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate and the like, and methyl acrylate, methyl methacrylate or methacrylic is preferable. Butyl acid, more preferably methyl methacrylate.

The crosslinked copolymer particles of (meth) acrylic acid ester and styrene may be crosslinked copolymer particles containing only monomer units derived from (meth) acrylic acid ester and styrene, and may be (meth). It may be a crosslinked copolymer particle containing a monomer unit other than the monomer unit derived from acrylic acid ester and styrene. In the crosslinked copolymer particles of the (meth) acrylic acid ester and styrene, the content ratio of the monomer unit derived from the (meth) acrylic acid ester and styrene to all the monomer units is 80% by mass. % Or more is preferable.

The content of the monomer unit derived from the (meth) acrylic acid ester in the crosslinked copolymer particles of the (meth) acrylic acid ester and styrene is preferably 50 to 99% by mass, and more preferably 60 to 90% by mass. It is 90% by mass. The content of the monomer unit derived from styrene in the crosslinked copolymer particles of the (meth) acrylic acid ester and styrene is preferably 1 to 50% by mass, more preferably 10 to 40% by mass. Is. (However, the total of the monomer unit derived from (meth) acrylic acid ester and the monomer unit derived from styrene is 100% by mass.)

The crosslinked copolymer particles of the (meth) acrylic acid ester and styrene are a single amount containing at least one selected from the (meth) acrylic acid ester, styrene, and if necessary, other monomers. It can be obtained by polymerizing the body component by a known method such as suspension polymerization.

Examples of the method for obtaining crosslinked acrylic particles include a method in which a monomer component is suspended and polymerized together with a crosslinking agent. As the cross-linking agent, it is preferable to use a compound having two or more unsaturated groups, and specific examples thereof include ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and divinylbenzene. ..

The volume median diameter of the organic particles is preferably 1 μm or more, more preferably 2 μm or more, still more preferably 3 μm or more, from the viewpoint of increasing the light scattering property in the summer when the temperature reaches around 40 ° C. The volume median diameter is preferably 10 μm or less, more preferably 8 μm or less, and further preferably 6 μm or less. The volume median diameter of organic particles is measured by the Coulter counter method. Further, in order to make the area ratio of the cross section of the dispersed phase having the equivalent circle diameter of 1 μm or more and 10 μm or less within the above-mentioned range, the volume is medium with respect to the components constituting the dispersed phase of the layer composed of the continuous phase and the dispersed phase. The proportion of organic particles having a diameter of 1 μm or more and 10 μm or less may be adjusted. For example, the content of organic particles having a volume median diameter of 1 μm or more and 10 μm or less with respect to 100 parts by mass of the components constituting the dispersed phase of the layer composed of the continuous phase and the dispersed phase is preferably 50 parts by mass or more. It is more preferably 70 parts by mass or more, and further preferably 90 parts by mass or more.

Examples of commercially available organic particles include Techpolymer (registered trademark) MSX series, Techpolymer (registered trademark) SSX series (all manufactured by Sekisui Plastics Co., Ltd.), Art Pearl (registered trademark) G series, and Art. Examples include Pearl (registered trademark) GS series (above, manufactured by Negami Kogyo Co., Ltd.), Ganz Pearl (registered trademark) GSM series (above, manufactured by Aika Kogyo Co., Ltd.) and the like.

(Inorganic particles)
Examples of the inorganic particles include glass particles, kaolin, aluminosilicate (zeolite) and the like.

The glass particles are particles containing silicon dioxide (SiO ₂ ), and are boron oxide (B ₂ O ₃ ), aluminum oxide (Al ₂ O ₃ ), sodium oxide (Na ₂ O), calcium oxide (CaO), and It may contain at least one inorganic compound selected from the group consisting of zinc oxide (ZnO). The glass particles may further contain additional inorganic compounds and additives, if desired. Specifically, in addition to the above-mentioned inorganic compounds, zirconium oxide, magnesium oxide, strontium oxide, lanthanum oxide, yttrium oxide, gadolinium oxide, bismuth oxide, antimony oxide, tantalum oxide, niobium oxide, tungsten oxide, magnesium carbonate, Conventional inorganic compounds such as silicon nitride, aluminum nitride, aluminum nitride, magnesium fluoride, calcium fluoride, sodium fluoride, lithium fluoride, and iron are appropriately mixed as necessary, and the agricultural film is linearly expanded as described above. It can be adjusted to be within the range of coefficients.

The shape of each of the inorganic particles is not particularly limited, and inorganic particles having various shapes such as spherical (for example, glass beads), fibrous (for example, chopped fiber, milled fiber), and flake-like can be used. ..

When the inorganic particles are spherical, their volume median diameter is preferably 1 μm or more, more preferably 2 μm or more, still more preferably 2 μm or more, from the viewpoint of increasing the light scattering property in the summer when the temperature reaches around 40 ° C. It is 3 μm or more. The volume median diameter is preferably 10 μm or less, more preferably 8 μm or less, and further preferably 6 μm or less. The volume median diameter of the particles is measured by laser diffraction. Further, in order to make the area ratio of the cross section of the dispersed phase having the equivalent circle diameter of 1 μm or more and 10 μm or less within the above-mentioned range, the volume is medium with respect to the components constituting the dispersed phase of the layer composed of the continuous phase and the dispersed phase. The ratio of inorganic particles having a diameter of 1 μm or more and 10 μm or less may be adjusted. For example, the content of the inorganic particles having a volume median diameter of 1 μm or more and 10 μm or less with respect to 100 parts by mass of the components constituting the dispersed phase of the layer composed of the continuous phase and the dispersed phase is preferably 50 parts by mass or more. It is more preferably 70 parts by mass or more, and further preferably 90 parts by mass or more.

When the inorganic particles are fibrous, the aspect ratio is not particularly limited, but from the viewpoint of increasing the light scattering property in the summer when the temperature reaches around 40 ° C, those having an aspect ratio of 1 to 500 are used, and the aspect ratio is 1. Those having an aspect ratio of about 100 are more preferably used, and those having an aspect ratio of 1 to 50 are further preferably used.

In addition, the inorganic particles may be surface-treated with a surface treatment agent such as a coupling agent.

(Dispersed phase thermoplastic resin, which is different from continuous phase thermoplastic resin)
The thermoplastic resin that can be contained in the dispersed phase may be any thermoplastic resin that can form a portion corresponding to an island in the sea-island structure in the thermoplastic resin that becomes the continuous phase, and is the thermoplastic used for the continuous phase. It is preferable to use a thermoplastic resin having a linear expansion coefficient smaller than that of the resin. When an olefin resin is used as the thermoplastic resin to be a continuous phase, for example, an uncrosslinked acrylic resin such as polymethyl methacrylate or methyl methacrylate-phenyl methacrylate copolymer, polyvinyl alcohol (PVOH), cyclic olefin Examples thereof include copolymers (COC).

The dispersed phase is at least one selected from organic particles, inorganic particles, and a thermoplastic resin different from the continuous phase, and an infrared absorber, a light stabilizer, etc., as long as the effects of the present invention are not impaired. It may contain at least one additive selected from UV absorbers, antifogging agents, antioxidants, antifogging agents, lubricants and the like.

Examples of the infrared absorber include hydrotalcite compounds and lithium-aluminum composite hydroxide. Specific examples of hydrotalcite compounds include natural hydrotalsite, trade names: DHT-4A (manufactured by Kyowa Chemical Industry Co., Ltd.), Magclear (manufactured by Toda Kogyo Co., Ltd.), Magcella (registered trademark) 1 (Kyowa Chemical Industry Co., Ltd.). (Manufactured by Co., Ltd.), Staviace (registered trademark) HT-P (manufactured by Sakai Chemical Industry Co., Ltd.) and the like. Specific examples of the lithium-aluminum composite hydroxide include OPTIMA-SS (manufactured by Toda Kogyo Co., Ltd.) and Mizusawa Lac (manufactured by Mizusawa Industrial Chemicals Co., Ltd.).

In one embodiment of the present invention, the hydrotalcite compounds may be used alone, or the lithium aluminum composite hydroxide may be used alone. Alternatively, both may be used in combination.

Examples of the light stabilizer include hindered amine compounds having the structure described in JP-A-8-73667. Specifically, trade names: Chinubin (registered trademark) 622, Kimasorb (registered trademark) 944, Kimasorb (registered trademark) 119 (all manufactured by BASF), Hostabin (registered trademark) N30, Hostabin (registered trademark) PR-31 (registered trademark) Examples thereof include Clarianto (registered trademark) UV3529 and Sayasorb (registered trademark) UV3346 (registered trademark).

Further, examples thereof include hindered amine compounds having the structures described in JP-A-11-315067, JP-A-2001-139821, WO2005 / 082852, and JP-A-2009-530428. Specifically, product names: NOR371 (manufactured by BASF), ADEKA STAB (registered trademark) LA-900 (manufactured by ADEKA Corporation), ADEKA STAB (registered trademark) LA-81 (manufactured by ADEKA Corporation), Hostabin (registered trademark) NOW (Made by Clariant Co., Ltd.).

Further, as the light stabilizer, an ethylene-cyclic aminovinyl compound copolymer having a monomer unit based on ethylene and a monomer unit based on a cyclic aminovinyl compound can also be mentioned. Examples of such an ethylene-cyclic aminovinyl compound copolymer include those having the structure described in JP-A-2002-265693.

The content of the light stabilizer contained in the resin composition constituting the layer composed of the continuous phase and the dispersed phase is preferably 0.01 to 3% by mass, more preferably 0.05 to 2% by mass, and particularly 0. It is preferably 1 to 1% by mass. However, the mass of the resin composition is 100% by mass.

Examples of the ultraviolet absorber include 2-hydroxybenzophenones, 2- (2'-hydroxyphenyl) benzotriazoles, benzoates, substituted oxanilides, cyanoacrylates, triazines and the like.

Examples of 2-hydroxybenzophenones include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and 5,5'-methylenebis (2-hydroxy-4-methoxy). Benzophenone) and the like.

Examples of 2- (2'-hydroxyphenyl) benzotriazoles include 2- (2'-hydroxy-5'-methylphenyl) benzotriazole and 2- (2'-hydroxy-3', 5'-ditertiary butyl. Phenyl) Benzotriazole, 2- (2'-hydroxy-3', 5'-ditertiary butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3'-tertiary butyl-5'- Methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-5'-tertiary octylphenyl) benzotriazole, 2- (2'-hydroxy-3', 5'-dicumylphenyl) benzotriazole, 2- (2-Hydroxy-3,5-ditertiary pentylphenyl) benzotriazole, 2,2'-methylenebis (4-third octyl-6-benzotriazolyl) phenol, 2- (2'-hydroxy- 3'-Triary butyl-5-carboxyphenyl) Benzotriazole and the like can be mentioned.

Examples of benzoates include phenylsalicylate, resorcinol monobenzoate, 2,4-ditertiary butylphenyl-3', 5'-ditertiary butyl-4'-hydroxybenzoate, and 2,4-ditertiary amylphenyl-3. '5'-Di-tertiary butyl-4'-hydroxybenzoate, hexadecyl-3,5-di-tertiary butyl-4-hydroxybenzoate and the like can be mentioned.

Examples of the substituted oxanilides include 2-ethyl-2'-ethoxyoxanilide, 2-ethoxy-4'-dodecyloxanilide and the like.

Examples of cyanoacrylates include ethyl-α-cyano-β, β-diphenyl acrylate, methyl-2-cyano-3-methyl-3- (p-methoxyphenyl) acrylate and the like.

Examples of triazines include 2- (4,6-diphenyl-1,3,5-triazine-2-yl) -5-[(hexyl) oxy] -phenol and 2- [4,6-bis (2,4). -Dimethylphenyl) -1,3,5-triazine-2-yl] -5- (octyloxy) phenol, 2- (2-hydroxy-4-octoxyphenyl) -4,6-bis (2,4-di) Tri-butylphenyl) -s-triazine, 2- (2-hydroxy-4-methoxyphenyl) -4,6-diphenyl-s-triazine, 2- (2-hydroxy-4-propoxy-5-methylphenyl)- Examples thereof include 4,6-bis (2,4-ditriary butylphenyl) -s-triazine.

2- (2'-Hydroxyphenyl) benzotriazoles are preferred, and 2- (2'-hydroxy-3'-tertiary butyl-5'-methylphenyl) -5-chlorobenzotriazoles are more preferred. 2- (2-Hydroxy-3,5-dithrench pentylphenyl) benzotriazole can be mentioned.

The UV absorbers are used alone or in combination of two or more. The content of the ultraviolet absorber contained in the resin composition constituting the layer composed of the continuous phase and the dispersed phase is preferably 0.001 to 3% by mass, more preferably 0.005 to 1% by mass. However, the mass of the resin composition is 100% by mass.

Examples of the antifogging agent include sorbitan fatty acid esters such as sorbitan monopalmitate, sorbitan monostearate, sorbitan monopalmitate, sorbitan monomontanate, sorbitan monooleate, and sorbitan dioleate, and sorbitan such as an alkylene oxide adduct thereof. Surfactants, Glycerin Monopalmitate, Glycerin Monostearate, Diglycerin Distearate, Triglycerin Monostearate, Tetraglycerin Dimontanate, Glycerin Monooleate, Diglycerin Monooleate, Diglycerin Sesquioleate, Glycerin-based surfactants such as tetraglycerin monooleate, hexaglycerin monooleate, hexaglycerin trioleate, tetraglycerin trioleate, tetraglycerin monolaurate, hexaglycerin monolaurate, and glycerin-based surfactants thereof and alkylene oxide adducts thereof. Agents, polyethylene glycol-based surfactants such as polyethylene glycol monopalmitate, polyethylene glycol monostearate, alkylene oxide adducts of alkylphenols, esters of sorbitan / glycerin condensates with organic acids, polyoxyethylene (2 mol) stearylamine , Polyoxyethylene (4 mol) stearylamine, polyoxyethylene (2 mol) stearylamine monostearate, polyoxyethylene (4 mol) laurylamine monostearate and other polyoxyethylene alkylamines and their fatty acid esters and the like. Examples include ionic surfactants. These may be used alone or in combination of two or more.

Examples of the antioxidant include phosphorus containing a trivalent phosphorus atom such as a so-called hindered phenol compound such as a 2,6-dialkylphenol derivative or a 2-alkylphenol derivative, a phosphite compound or a phosphonite compound. Examples include system ester compounds. These antioxidants may be used alone or in combination of two or more. In particular, from the viewpoint of hue stabilization, it is preferable to use a hindered phenol-based compound and a phosphorus-based ester compound in combination.

Examples of the antifogging agent include a fluorine compound having a perfluoroalkyl group, an ω-hydrofluoroalkyl group, etc. (particularly a fluorine-based surfactant), and a silicone-based compound having an alkylsiloxane group (particularly a silicone-based surfactant). ) Etc. can be mentioned. Specific examples of the fluorosurfactant include Unidyne (registered trademark) DSN-403N, DS-403, DS-406, DS-401 (trade name) manufactured by Daikin Industries, Ltd., and Surflon manufactured by AGC Seimi Chemical Co., Ltd. (Registered trademark) KC-40, AF-1000, AF-2000 (trade name) and the like can be mentioned, and SH-3746 (trade name) manufactured by Toray Dow Corning Co., Ltd. can be mentioned as a silicone-based surfactant. These may be used alone or in combination of two or more. The content of the antifog agent contained in the resin composition constituting the layer composed of the continuous phase and the dispersed phase is preferably 0.01 to 3% by mass, more preferably 0.02 to 2% by mass, and 0.05. ~ 1% by mass is particularly preferable. However, the mass of the resin composition is 100% by mass.

[Other layers]
The agricultural film according to one embodiment of the present invention may be a film having only a layer composed of a continuous phase and a dispersed phase, or a film having a layer other than a layer composed of a continuous phase and a dispersed phase. Good. As one of the preferred forms of the film of the present invention, a multilayer film in which an intermediate layer composed of a continuous phase and a dispersed phase exists between two polyolefin-based resin layers can be mentioned. This layer structure has the advantage that the strength of the film can be improved.

The two polyolefin resin layers in the multilayer film may be the same or different. More specifically, as the structure of the multilayer film, 2 types 3 layers, 3 types 3 layers, 3 types 4 layers, 4 types 4 layers, 4 types 5 layers, 5 types 5 layers and the like can be exemplified.

When the multilayer film is composed of four or more types of layers, it may have a layer different from both the continuous phase and the dispersed phase layer and the polyolefin-based resin layer, and has three or more polyolefin-based resin layers. You may. Further, there may be two or more layers composed of a continuous phase and a dispersed phase.

For example, when the polyolefin-based agricultural film is a five-layer film, when the polyolefin-based resin layer is A and the intermediate layer composed of the continuous phase and the dispersed phase is B, A, and the layer different from B is C, C / A. / B / A / C, A / B / A / C / C, A / A / B / A / A, A / A / B / B / A, A / B / A / B / A, etc. There may be.

When the film according to one embodiment of the present invention is a multilayer film composed of three layers, the ratio of the thickness of each layer is such that the coefficient of linear expansion is 1.5 × 10 ^-4 K ^-1 or more and 2.8 × 10. Adjust appropriately so that it is ^-4 K ^-1 or less. For example, the coefficient of linear expansion can be increased by increasing the ratio of the thickness of the layer composed of the continuous phase and the dispersed phase to the thickness of the entire agricultural film. For example, when the agricultural film according to one aspect consists only of a layer composed of a continuous phase and a dispersed phase, it is preferable that the thickness of the film is in the range of 1 μm or more and 500 μm or less, as has already been explained. When the agricultural film is a multilayer film, the thickness of the multilayer film is within the range of 1 μm or more and 500 μm or less from the viewpoint of the balance between the temperature sensitivity around 0 ° C. to 40 ° C. and the strength of the film. The thickness ratio of the polyolefin-based resin layer / the layer composed of the continuous phase and the dispersed phase / the polyolefin-based resin layer is preferably 1/2/1 to 1/4/1.

The polyolefin-based resin layer constituting the multilayer film contains a polyolefin-based resin. As the polyolefin-based resin, the polyolefin-based resin described above in [Continuous Phase] can be used. Only one type of polyolefin resin may be used, or two or more types may be used in combination.

The polyolefin-based resin layer may contain, if necessary, a light stabilizer, an ultraviolet absorber, an antifogging agent, an antioxidant, an antifogging agent, a lubricant, an antiblocking agent, an antistatic agent, a pigment, and the like. It is good, but the continuous phase does not contain at least one component selected from a thermoplastic resin different from the thermoplastic resin of the continuous phase of the organic particles, the inorganic particles and the continuous phase and the dispersed phase. It can be distinguished from the layer consisting of and the dispersed phase.

The film according to one embodiment of the present invention may have an antifogging coating layer as one surface layer or on both sides. Examples of such an antifogging coating layer include an antifogging layer made of an inorganic colloid and an antifogging coating layer containing an inorganic colloid and a binder resin.

The inorganic colloid imparts hydrophilicity to the surface of a hydrophobic polyolefin resin film, and is usually used in the form of a sol in which the inorganic colloid is dispersed in a liquid dispersion medium such as water. Specific examples thereof include silica sol and alumina sol, and silica sol is preferable.

Examples of the binder resin include polyurethane-based resins, acrylic-based resins, acrylic-modified polyurethane-based resins, polyester-based resins, and epoxy-based resins.

The binder resin is usually used as an aqueous emulsion in which the resin is dispersed in a mixed solvent of water or water and an aqueous solvent such as alcohol.

The antifogging coating layer is preferably an antifogging layer containing silica and a binder resin. Further, as the binder resin, a polyurethane resin, an acrylic resin, and an acrylic modified polyurethane resin are preferable.

Preferred silica includes spherical silica having an average particle diameter of 5 to 100 nm.

When the total of silica and binder resin contained in the antifogging coating layer is 100% by mass, the content of silica is 30 to 70% by mass and the content of binder resin is 30 to 70% by mass. The content of silica is preferably 50 to 65% by mass, and the content of binder resin is more preferably 35 to 50% by mass. If the silica content is too low, a sufficient antifogging effect cannot be obtained, and conversely, if the silica content is too high, the coating film becomes cloudy and the light transmittance at low temperature can be lowered.

The antifogging coating layer containing silica and a binder resin can be formed, for example, as shown below. An aqueous emulsion containing a binder resin, an aqueous silica sol containing silica, and water as a dispersion medium are mixed and stirred to obtain a coating liquid. Next, the antifogging layer can be formed by applying this coating liquid by a known means and drying it. Specific examples of the coating means include bar coating, gravure coating, reverse coating, brush coating, spray coating, kiss coating, die coating, dipping and the like. Examples of the drying means include hot air drying.

The thickness of the coating film composed of silica and the binder resin is preferably 0.3 to 1.5 μm, more preferably 0.5 to 1.2 μm.

The coating liquid may contain a silicone-based surfactant and a fluorine-based surfactant in order to improve the coatability. Examples of the silicone-based surfactant include polyether-modified silicone oil.

Further, a cross-linking agent, a light stabilizer, and an ultraviolet absorber may be added to the coating liquid, if necessary.

The antifogging coating layer may be formed as one surface layer of the film, or may be formed as both surface layers. Further, the antifogging layer may be a single layer film or a multilayer film having two or more layers.

<Agricultural and horticultural facilities>
In the agricultural and horticultural facilities covered with the agricultural film according to one embodiment of the present invention, since the light scattering property of the film is high in the summer when the temperature reaches around 40 ° C., obstacles such as leaf burning of crops due to excessive direct light are observed. Can be prevented. In addition, since the light scattering property of the film is low in winter when the temperature reaches around 0 ° C., sufficient direct light can be delivered to the crop. It can be used all year round and can deliver a stable amount of light. The agricultural and horticultural facilities are suitably used for cultivating spinach, tomatoes, leeks, cucumbers, strawberries and the like.

Examples of agricultural and horticultural facilities equipped with an agricultural film according to an embodiment of the present invention include greenhouses and tunnels for plant cultivation. In an agricultural and horticultural facility, the agricultural film is spread on, for example, an agricultural and horticultural facility frame.

Further, when the agricultural film according to one embodiment of the present invention is spread in an agricultural and horticultural facility, for example, the agricultural film is caught in the agricultural and horticultural facility frame for spreading in the agricultural and horticultural facility and is broken. It is one of the advantages that it is extremely easy to handle because it can be suitably prevented. Therefore, a method of extending to an agricultural and horticultural facility using an agricultural film according to an embodiment of the present invention and an agricultural and horticultural facility extended using an agricultural film are also within the scope of the present invention.

Hereinafter, examples of the present invention will be shown. The test methods in Examples and Comparative Examples are as follows.

[Test method]
<Coefficient of linear expansion>
A 5 mm × 5 mm test piece was cut out from the film and set in a thermomechanical analyzer (product name: TMA402 F1 Hyperion (manufactured by NETZSCH)) set to the compression mode, the load was 0.05 N, and the test piece was -15 ° C. It was cooled to the following. Then, the length in the direction perpendicular to the surface at 0 ° C. and 25 ° C., that is, the thickness was measured while raising the temperature to 60 ° C. at a rate of 5 ° C./min. The measurement was performed in a helium atmosphere.

From the lengths (thickness) L _{0 ° C.} and L _{25 ° C.} in the direction perpendicular to the surface of the test piece at 0 ° C. and 25 ° C. obtained as described above, the coefficient of linear expansion was calculated by the following formula (1).
Coefficient of linear expansion = (L _{25 ° C-} L _{0 ° C} ) / (25 ° C-0 ° C) (1)
The above operation was performed at two locations in the film, and the average value was taken as the coefficient of linear expansion of the film.

<Ratio of the cross-sectional area of the dispersed phase with a circle-equivalent diameter of 1 μm or more and 10 μm or less to the cross-sectional area of the intermediate layer>
The film was cut in the direction perpendicular to the film surface and in the direction parallel to the slow axis in the film surface. Using an optical microscope (manufactured by Nikon Corporation, ECLIPSE (registered trademark) LV100DA-U), the observation magnification was set to 500 times, and images of two arbitrary cross sections of the film were acquired. The length of the cross-sectional image of the film in the direction parallel to the slow axis described in the examples described later was 238 μm, which is equivalent to the actual size. The slow axis of the film was determined at a wavelength of 586 nm using a phase difference measuring device (KOBRA (registered trademark) -WPR manufactured by Oji Measuring Instruments Co., Ltd.).

Next, using an image analysis system (LUZEX (registered trademark) -AP manufactured by Nireco Co., Ltd.), a dispersed phase having a circle-equivalent diameter of 1 μm or more and 10 μm or less with respect to the cross-sectional area of the intermediate layer in the cross-sectional image of the film. The ratio of the cross-sectional area (hereinafter, may be referred to as the dispersed phase ratio of the equivalent circle diameter of 1 μm or more and 10 μm or less) was determined. The dispersed phase ratio of the circle equivalent diameter of 1 μm or more and 10 μm or less was obtained for each of the two cross-sectional images, and the average value was taken as the dispersed phase ratio of the circle equivalent diameter of 1 μm or more and 10 μm or less.

<Haze value>
Measurements were carried out at 0 ° C. and 40 ° C. using a temperature control haze meter (THM-150TL) manufactured by Murakami Color Technology Research Institute Co., Ltd. Measurement conditions other than temperature were based on JIS K 7136: 2000.

<1% SM> (Unit: MPa)
A test piece with a width of 20 mm and a length of 125 mm is cut out, attached to a tensile tester (manufactured by Shimadzu Corporation, AGS-100B) with a distance between chucks of 5 cm, pulled at a speed of 5 mm / min, and the load at 1% elongation is calculated. , Calculated by the following formula (2).
1% SM = F / S / 0.01 (2)
Here, F represents the load when the test piece is extended by 1%, and S represents the initial area of the cross section perpendicular to the tensile direction of the test piece.
For the film produced by the inflation molding machine, measurements were taken when the MD direction was the tensile direction and when the TD direction was the tensile direction.

[material]
The materials used are shown below.

The MFR described below corresponds to a value measured by the A method or the B method under the condition of a load of 21.18 N at a predetermined temperature in accordance with JIS K 7210: 1999.
Ethylene copolymer:
(1) Ethylene-methyl methacrylate copolymer (hereinafter referred to as EMMA-1)
MFR (190 ° C, 21.18N, method A) 7g / 10 minutes
Content of monomer unit derived from ethylene 75% by mass, content of monomer unit derived from methyl methacrylate (MMA) 25% by mass (Mass of EMMA-1 is 100% by mass)
(Aklift (registered trademark) WK307 manufactured by Sumitomo Chemical Co., Ltd.)
(2) Ethylene-methyl methacrylate copolymer (hereinafter referred to as EMMA-2)
MFR (190 ° C, 21.18N, method A) 2g / 10 minutes
Content of monomer unit derived from ethylene 80% by mass, content of monomer unit derived from methyl methacrylate (MMA) 20% by mass (Mass of EMMA-2 is 100% by mass)
(Aklift (registered trademark) WH206-F manufactured by Sumitomo Chemical Co., Ltd.)
(3) Ethylene-methyl methacrylate copolymer (hereinafter referred to as EMMA-3)
MFR (190 ° C, 21.18N, method A) 2g / 10 minutes
Content of monomer unit derived from ethylene 90% by mass, content of monomer unit derived from methyl methacrylate (MMA) 10% by mass (Mass of EMMA-3 is 100% by mass)
(Aklift (registered trademark) WD201-F manufactured by Sumitomo Chemical Co., Ltd.)
(4) Ethylene-methyl methacrylate copolymer (hereinafter referred to as EMMA-4)
MFR (190 ° C, 21.18N, method B) 450g / 10 minutes
Content of monomer unit derived from ethylene 68% by mass, content of monomer unit derived from methyl methacrylate (MMA) 32% by mass (Mass of EMMA-4 is 100% by mass)
(Aklift (registered trademark) CM5022 manufactured by Sumitomo Chemical Co., Ltd.)
(5) Ethylene-vinyl acetate copolymer (EVA) (hereinafter referred to as EVA-1)
MFR (190 ° C, 21.18N, method A) 7g / 10 minutes
The content of the monomer unit derived from ethylene is 72% by mass, and the content of the monomer unit derived from vinyl acetate (VA) is 28% by mass (the mass of EVA-1 is 100% by mass).
(Sumitate (registered trademark) KA-30 manufactured by Sumitomo Chemical Co., Ltd.)
(6) Ethylene-1-hexene copolymer (hereinafter referred to as ER-1)
MFR (190 ° C, 21.18N, method A) 3.2 g / 10 minutes
(Excellen FX307 manufactured by Sumitomo Chemical Co., Ltd.)
Propylene polymer:
(1) Propylene-ethylene random copolymer (hereinafter referred to as rPP-1)
MFR (230 ° C, 21.18N, method A) 1.5g / 10 minutes
(Noblen (registered trademark) S131 manufactured by Sumitomo Chemical Co., Ltd.)
Polyolefin resin:
(1) Polyethylene resin (PE) (hereinafter referred to as PE-1)
MFR (190 ° C, 21.18N, method A) 0.5g / 10 minutes
(Excellen (registered trademark) GMH GH030, manufactured by Sumitomo Chemical Co., Ltd.)
(2) Polyethylene resin (PE) (hereinafter referred to as PE-2)
MFR (190 ° C, 21.18N, method A) 0.4 g / 10 minutes
(Excellen (registered trademark) GMH GH051 manufactured by Sumitomo Chemical Co., Ltd.)
particle:
(1) OMicron (registered trademark) NP5-P0 (glass beads manufactured by Sovitec) (hereinafter referred to as particle-1)
Medium volume diameter = 5 μm (laser diffraction method)
Refractive index (23 ° C) = 1.51
(2) OMicon (registered trademark) NP3-P0 (Glass beads manufactured by Sovitec) (hereinafter referred to as particle-2)
Medium volume diameter = 3 μm (laser diffraction method)
Refractive index (23 ° C) = 1.51
(3) Crosslinked methyl methacrylate-styrene copolymer particles (hereinafter referred to as particle-3)
Medium volume diameter = 5 μm (Coulter counter method)
Refractive index (23 ° C) = 1.51
(Techpolymer MSX-5Z Sekisui Plastics Co., Ltd.)
The films of Examples 1 to 4 and Comparative Example 1 provided with the layer of the resin composition were prepared and evaluated.

[Example 1]
EMMA-1 75% by mass and particles-225% by mass are mixed, subjected to a lab plast mill (manufactured by Toyo Seiki Seisakusho Co., Ltd.), kneaded at a temperature of 150 ° C. and a rotation speed of 60 rpm for 5 minutes to form a resin composition. I got something. The resin composition was press-molded at 150 ° C. and then press-cooled at 10 ° C. to obtain a film having a thickness of 100 μm. Table 2 shows the linear expansion coefficient of the obtained film, the dispersed phase ratio of the equivalent circle diameter of 1 μm or more and 10 μm or less, the haze value at 0 ° C. and 40 ° C., and the value of 1% SM at 23 ° C.

[Example 2]
A resin composition and a film were obtained in the same manner as in Example 1 except that EMMA-2 was used instead of EMMA-1 and particle-1 was used instead of particle-2. Table 2 shows the linear expansion coefficient of the obtained film, the dispersed phase ratio of the equivalent circle diameter of 1 μm or more and 10 μm or less, the haze value at 0 ° C. and 40 ° C., and the value of 1% SM at 23 ° C.

[Example 3]
EVA-1 45% by mass, ER-1 20% by mass, rPP-1 20% by mass, and particle-3 15% by mass were mixed and subjected to a lab plastic mill (manufactured by Toyo Seiki Seisakusho Co., Ltd.) at a temperature. Kneading was carried out at 150 ° C. and a rotation speed of 60 rpm for 5 minutes to obtain a resin composition. The resin composition was press-molded at 150 ° C. and then press-cooled at 30 ° C. to obtain a film having a thickness of 100 μm. Table 2 shows the linear expansion coefficient of the obtained film, the dispersed phase ratio of the equivalent circle diameter of 1 μm or more and 10 μm or less, the haze value at 0 ° C. and 40 ° C., and the value of 1% SM at 23 ° C.

[Example 4]
<Masterbatch>
A masterbatch consisting of 50 parts by weight of EVA-1 and -50 parts by weight of particles was used. This masterbatch was designated as MB-1.

<Production of film>
Three-layer inflation equipped with an inner layer extruder (40 mm extruder), an intermediate layer extruder (40 mm extruder), an outer layer extruder (40 mm extruder), and a 100 mmφ die (lip gap 1.2 mm). A three-layer tubular film was molded using a molding machine (manufactured by Placo Co., Ltd.).

Specifically, the material of the polyolefin resin composition for the outer layer is put into the extruder for the outer layer, the material of the resin composition for the intermediate layer of Example 4 is put into the extruder for the middle layer, and the polyolefin resin for the inner layer is put into the extruder. The material of the composition is put into an extruder for an inner layer, melt-kneaded in each extruder, and then discharged from a 100 mmφ die so that the inner layer is 30 μm, the intermediate layer is 90 μm, and the outer layer is 30 μm (total thickness is 150 μm). The amount was adjusted, and the melted resin composition of each layer was extruded and cooled to obtain a three-layer tubular film. At this time, the temperature of the extruder for the inner layer and the extruder for the outer layer was set to 160 ° C, and the temperature for the extruder and the die for the intermediate layer was set to 150 ° C.

The materials of the polyolefin-based resin composition for the outer layer were PE-1 and PE-2, and the blending amounts were 50% by mass for PE-1 and 50% by mass for PE-2. The materials of the resin composition for the intermediate layer of Example 4 are EVA-1, ER-1, rPP-1, and MB-1, and the blending amount is 30% by mass of EVA-1 and ER. -1 was 20% by mass, rPP-1 was 20% by mass, and MB-1 was 30% by mass. The material of the polyolefin-based resin composition for the inner layer was the same as the material of the polyolefin-based resin composition for the outer layer.

Table 2 shows the linear expansion coefficient of the obtained film, the dispersed phase ratio of the equivalent circle diameter of 1 μm or more and 10 μm or less, the haze value at 0 ° C. and 40 ° C., and the value of 1% SM at 23 ° C.

[Example 5]
<Production of film>
The materials of the polyolefin resin composition for the outer layer were PE-1 and PE-2, and the blending amounts were 50% by mass for PE-1 and 50% by mass for PE-2. The materials of the resin composition for the intermediate layer of Example 5 are EVA-1, ER-1, rPP-1, and MB-1, and the blending amount of EVA-1 is 10% by mass and ER. -1 was 40% by mass, rPP-1 was 20% by mass, and MB-1 was 30% by mass. The material of the polyolefin-based resin composition for the inner layer was the same as the material of the polyolefin-based resin composition for the outer layer. A three-layer multilayer film was obtained in the same manner as in Example 4 except for the above.

Table 2 shows the linear expansion coefficient of the obtained film, the dispersed phase ratio of the equivalent circle diameter of 1 μm or more and 10 μm or less, the haze value at 0 ° C. and 40 ° C., and the value of 1% SM at 23 ° C.

[Comparative Example 1]
A resin composition and a film were obtained in the same manner as in Example 2 except that EMMA-3 was used instead of EMMA-2. Table 2 shows the linear expansion coefficient of the obtained film, the dispersed phase ratio of the equivalent circle diameter of 1 μm or more and 10 μm or less, the haze value at 0 ° C. and 40 ° C., and the value of 1% SM at 23 ° C.

[Comparative Example 2]
EMMA-1 50% by mass, EMMA-4 25% by mass, and particles-125% by mass are mixed and subjected to a lab plastic mill (manufactured by Toyo Seiki Seisakusho Co., Ltd.) at a temperature of 100 ° C. and a rotation speed of 60 rpm. Kneaded for 5 minutes to obtain a resin composition. The resin composition was press-molded at 100 ° C. and then press-cooled at 10 ° C. to obtain a film having a thickness of 100 μm. Table 2 shows the linear expansion coefficient of the obtained film, the dispersed phase ratio of the equivalent circle diameter of 1 μm or more and 10 μm or less, the haze value at 0 ° C. and 40 ° C., and the value of 1% SM at 23 ° C.

[Comparative Example 3]
<Masterbatch>
Intensive mixer (manufactured by Nippon Roll Mfg. Co., Ltd.) with 49.2 parts by mass of EMMA-2, 50 parts by mass of particles, and 0.8 parts by mass of Irganox (registered trademark) 1010 (manufactured by BASF) as an antioxidant. And mixed at 160 ° C for 5 minutes, and the obtained mixture is supplied to a 65 mmφ single-screw extruder (manufactured by Japan Steel Works, Ltd.), extruded, and pelletized for the resin composition for the intermediate layer. I got a masterbatch of. This masterbatch was designated as MB-2.

<Production of film>
Three-layer inflation equipped with an inner layer extruder (40 mm extruder), an intermediate layer extruder (40 mm extruder), an outer layer extruder (40 mm extruder), and a 100 mmφ die (lip gap 1.2 mm). A three-layer tubular film was molded using a molding machine (manufactured by Placo Co., Ltd.).

Specifically, the material of the polyolefin resin composition for the outer layer is put into the extruder for the outer layer, the material of the resin composition for the intermediate layer of Comparative Example 3 is put into the extruder for the middle layer, and the polyolefin resin for the inner layer is put into the extruder. The material of the composition is put into an extruder for the inner layer, melt-kneaded in each extruder, and then discharged from a 100 mmφ die so that the inner layer is 50 μm, the intermediate layer is 50 μm, and the outer layer is 50 μm (total thickness is 150 μm). The amount was adjusted, and the melted resin composition of each layer was extruded and cooled to obtain a three-layer tubular film. At this time, the temperature of the extruder for the inner layer and the extruder for the outer layer was set to 160 ° C, and the temperature for the extruder and the die for the intermediate layer was set to 150 ° C.

The materials of the polyolefin-based resin composition for the outer layer were PE-1 and PE-2, and the blending amounts were 50% by mass for PE-1 and 50% by mass for PE-2. The materials of the resin composition for the intermediate layer of Comparative Example 3 were EMMA-2 and MB-2, and the blending amounts were 50% by mass for EMMA-2 and 50% by mass for MB-2. .. The material of the polyolefin-based resin composition for the inner layer was the same as the material of the polyolefin-based resin composition for the outer layer.

Table 2 shows the linear expansion coefficient of the obtained film, the dispersed phase ratio of the equivalent circle diameter of 1 μm or more and 10 μm or less, the haze value at 0 ° C. and 40 ° C., and the value of 1% SM at 23 ° C.

[Comparative Example 4]
<Production of film>
The materials of the polyolefin resin composition for the outer layer were PE-1 and PE-2, and the blending amounts were 50% by mass for PE-1 and 50% by mass for PE-2. The materials of the resin composition for the intermediate layer of Comparative Example 4 were EMMA-1 and MB-2, and the blending amounts were 50% by mass for EMMA-1 and 50% by mass for MB-2. .. The material of the polyolefin-based resin composition for the inner layer was the same as the material of the polyolefin-based resin composition for the outer layer. A three-layer multilayer film was obtained in the same manner as in Comparative Example 3 except for the above.

Table 2 shows the linear expansion coefficient of the obtained film, the dispersed phase ratio of the equivalent circle diameter of 1 μm or more and 10 μm or less, the haze value at 0 ° C. and 40 ° C., and the value of 1% SM at 23 ° C.

If the coefficient of linear expansion of the agricultural film is 1.5 × 10 ^-4 K ^-1 or more and 2.8 × 10 ^-4 K ^-1 or less, the haze value in the temperature range of 0 ° C. to 40 ° C. It was confirmed that the change, that is, the change in haze value over a temperature range higher than 25 ° C. was large. Furthermore, it was confirmed that when the coefficient of linear expansion was 2.8 × 10-4K-1, the value of 1% SM at 23 ° C. was also high.

The agricultural film according to the present invention can be suitably used as a covering material or the like in agricultural and horticultural facilities such as greenhouses and tunnels for plant cultivation.

Claims (5)

An agricultural film having at least one layer consisting of a continuous phase and a dispersed phase and satisfying the following (A) and (B);
(A) A cross section of the dispersed phase having a circular equivalent diameter of 1 μm or more and 10 μm or less in the cross section cut in the direction perpendicular to the film surface and in the direction parallel to the slow phase axis in the film surface. The ratio of the area is 1% or more and 30% or less with respect to the cross-sectional area of the layer.
(B) The coefficient of linear expansion calculated by the following formula (1) is 1.5 × 10 ^-4 K ^-1 or more and 2.8 × 10 ^-4 K ^-1 or less.
Coefficient of linear expansion = (L _{25 ° C-} L _{0 ° C} ) / (25 ° C-0 ° C) (1)
Here, L _{25 ° C.} represents the length of the film in the direction perpendicular to the film surface at 25 ° C., and L _{0 ° C.} represents the length of the film in the direction perpendicular to the film surface at 0 ° C. .. The agricultural film according to claim 1, wherein the continuous phase contains a thermoplastic resin. The agricultural film according to claim 2, wherein the thermoplastic resin is a polyolefin resin. The agricultural film according to any one of claims 1 to 3, wherein the refractive index of the component contained in the dispersed phase is 1.50 or more and 1.53 or less. An agricultural and horticultural facility in which the agricultural film according to any one of claims 1 to 4 is spread on an agricultural and horticultural facility frame.